Phase detector and method of phase detection

ABSTRACT

In order to provide a phase detector and a method of phase detection which are distinguished by greater sensitivity and simple implementability, at least one differential signal of two input signals (U a ; U b ) may be formed over at least one predefined period by means of a first subtracter ( 12 ), at least one maximum value of the at least one differential signal may be detected by means of a first peak detector ( 16 ) and at least one minimum value of the at least one differential signal may be detected by means of a second peak detector ( 18 ) and at least one further differential signal (U out ) may be formed from the at least one maximum value and the at least one minimum value by means of a second subtracter ( 14 ).

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C 371 of InternationalPatent Application Number PCT/IB04/50705, filed May 14, 2004.

The invention relates to a phase detector and a method of phasedetection having the features stated in the precharacterizing clauses ofclaims 1 and 6.

Phase detectors generally fulfill the task of quantifying a time shiftin periodic signals of the same frequency However, the sensitivity ofconventional phase detectors is in need of improvement.

It is therefore an object of the invention to provide a phase detectorand a method of phase detection which are distinguished by greatersensitivity and simple implementability.

This object is achieved according to the invention by a phase detectorand a method of phase detection having the features stated in claims 1and 6. The phase detector according to the invention is characterized inthat at least one differential signal of two input signals may be formedover at least one predefined period by means of a fist subtracter, atleast one maximum value of the at least one differential signal may bedetected by means of a first peak detector and at least one minimumvalue of the at least one differential signal may be detected by meansof a second peak detector and at least one further differential signalmay be formed from the at least one maximum value and the at least oneminimum value by means of a second subtracter. The value of the furtherdifferential signal is a measure of the magnitude of the phase shift ofthe input signals. Such a phase detector is distinguished by its greatersensitivity and particularly simple implementability.

In a preferred development of the invention, the phase detector ismonolithically integrated. In this way, increased economic viability isadvantageously achieved.

Furthermore, in a preferred development of the invention the phasedetector is integrated into a smart card. This advantageously opens upmany different areas of application of the phase detector according tothe invention.

Moreover, in a preferred development of the invention at least one ofthe signals to be processed is an electrical, audible or visual signalor the like. In this way, particularly favorable properties areadvantageously achieved, wherein this embodiment is distinguished by aparticularly large number of possible applications.

In addition, in a preferred development of the invention at least one ofthe signals to be processed may substantially be described by a Fourierseries. In this way, particularly advantageous possible uses areachieved.

The method of phase detection according to the invention ischaracterized in that at least one differential signal of two inputsignals is formed over at least one predefined period, at least onemaximum value and at least one minimum value of the at least onedifferential signal is detected and at least one further differentialsignal is formed from the at least one maximum value and the at leastone minimum value. The value of the further differential signal is ameasure of the magnitude of the phase shift of the input signals. Thismethod is distinguished by its greater sensitivity and particularlysimple implementability.

The method according to the invention is preferably characterized inthat formation of at least one difference is effected by means of asubtracter and, also preferably, detection of the at least one maximumvalue and/or the at least one minimum value is effected by means of apeak detector. This makes the method particularly simple to implement.

Furthermore, the method according to the invention is preferablycharacterized in that at least one of the signals to be processed is anelectrical, audible or visual signal or the like. In this way,particularly favorable properties are advantageously achieved, whereinthis method is distinguished by a particularly large number of possibleapplications.

Finally, the method according to the invention is preferablycharacterized in that at least one of the signals to be processed maysubstantially be described by a Fourier series. In this way,particularly advantageous possible applications are achieved.

Further preferred developments of the invention are revealed by theremaining features stated in the dependent claims.

The invention will be further described with reference to examples ofembodiment shown in the drawings to which, however, the invention is notrestricted.

The FIGURE shows a block diagram of one embodiment of a phase detector100 according to the invention, which comprises a first subtracter 12, asecond subtracter 14, a first peak detector 16 and a second peakdetector 18. Subtracters 12 and 14 and peak detectors 16 and 18 may inturn also be assembled from a plurality of sub-components. Likewise, acombination of a plurality of components of the phase detector 100, suchas in particular a monolithic integration on a microchip or in anexisting microchip, is also feasible. Two input signals U_(a) and U_(b)of substantially the same frequency are subtracted time wise from oneanother by means of the first subtracter 12. The difference between thefunctions of the two input signals U_(a) and U_(b) is itself anoscillation with a minimum value and a maximum value. These are furtherremoved from one another, the greater the phase shift of the two inputsignals U_(a) and U_(b). The maximum value of the differential signalarising is then detected by means of the first peak detector 16 and theminimum value by means of the second peak detector 18. The differencebetween the two extrema is then formed by means of the second subtracter14. This further differential signal U_(out) is a measure of themagnitude of the phase shift of the input signals U_(a) and U_(b) andforms the output signal U_(out) of the phase detector 100. The functionof the output signals U_(out) forms a minimum value in the case of phasecoincidence of the input signals U_(a) and U_(b). The phase detector 100may be used in a phase shift range of from −180° to +180°, wherein nosign recognition takes place.

LIST OF REFERENCE NUMERALS

100 Phase detector 12 First subtracter 14 Second subtracter 16 Firstpeak detector, maximum value 18 Second peak detector, minimum valueU_(a) Input signal U_(b) Input signal U_(out) Further differentialsignal, output signal

1. A phase detector, wherein at least one differential signal of twoinput signals may be formed over at least one predefined period by meansof a first subtracter at least one maximum value of the at least onedifferential signal may be detected by means of a first peak detectorand at least one minimum value of the at least one differential signalmay be detected by means of a second peak detector and at least onefurther differential signal may be formed from the at least one maximumvalue and the at least one minimum value by means of a secondsubtracter.
 2. A phase detector as claimed in claim 1, characterized inthat the phase detector (100) is monolithically integrated.
 3. A phasedetector as claimed in claim 1 characterized in that the phase detectoris integrated into a smart card.
 4. A phase detector as claimed in claim1 characterized in that at least one of the signals to be processed isan electrical, audible or visual signal or the like.
 5. A phase detectoras claimed in claim 1 characterized in that at least one of the signalsto be processed may substantially be described by a Fourier series.
 6. Amethod of phase detection, wherein at least one differential signal oftwo input signals is formed over at least one predefined period, atleast one maximum value and at least one minimum value of the at leastone differential signal is detected and at least one furtherdifferential signal is formed from the at least one maximum value andthe at least one minimum value.
 7. A method as claimed in claim 6,characterized in that the formation of at least one difference iseffected by means of a subtracter (14).
 8. A method as claimed in claim6 characterized in that detection of the at least one maximum valueand/or of the at least one minimum value is effected by means of a peakdetector.
 9. A method as claimed in claim 6 characterized in that atleast one of the signals to be processed is an electrical, audible orvisual signal or the like.
 10. A method as claimed in claim 6characterized in that at least one of the signals to be processed maysubstantially be described by a Fourier series.